Magnet Holder Camera Actuator for Low-Parasitic Lens Motion
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Solution Overview
Problem
Small form factor cameras face challenges in achieving high image quality due to parasitic motion in degrees of freedom other than the optical axis, which complicates the integration of autofocus and optical image stabilization mechanisms.
Innovation Solution
A camera design incorporating a lens assembly, an image sensor, and a voice coil motor with a spring suspension assembly, permanent magnets, and a magnet holder assembly that generates a holder magnetic field, allowing for precise movement of the lens assembly for autofocus and optical image stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small form factor camera integrates both autofocus and optical image stabilization mechanisms, then the camera can achieve high image quality, but parasitic motion occurs in degrees of freedom other than the optical axis
Solution Approach 1:
The lens assembly is divided into multiple independent lens elements that can be moved separately. The autofocus mechanism moves the entire lens assembly along the optical axis, while the optical image stabilization mechanism independently moves specific lens elements in orthogonal directions to counteract parasitic motion, thereby achieving both functions without interference
Solution Approach 2:
A magnetic field is introduced as an intermediary between the permanent magnets and the lens assembly. The voice coil motor generates a controllable magnetic field that interacts with the permanent magnets to produce precise forces for optical image stabilization, enabling fine control of lens element positions without mechanical contact that could cause parasitic motion
2Device complexity
If the lens assembly is moved as a single rigid body for autofocus, then the focusing mechanism is simple, but parasitic motion in orthogonal directions cannot be corrected
Solution Approach 1:
The lens assembly is segmented into multiple movable lens elements. The autofocus mechanism maintains simplicity by moving the entire assembly along the optical axis, while individual lens elements can be independently adjusted by the optical image stabilization mechanism to correct parasitic motion in orthogonal directions
Solution Approach 2:
The lens assembly transitions from a static rigid body to a dynamic system with multiple degrees of freedom. While the overall assembly moves for autofocus, individual lens elements can dynamically adjust their positions in response to detected parasitic motion, enabling both simple autofocus and effective stabilization
3Reliability
If optical image stabilization adjusts lens location on X and Y axes, then parasitic motion is compensated, but the device complexity increases
Solution Approach 1:
The permanent magnets and voice coil motor serve multiple functions: they enable both autofocus by moving the lens assembly along the optical axis and optical image stabilization by adjusting lens element positions in orthogonal directions. This multi-functionality reduces overall device complexity compared to having separate mechanisms for each function
Solution Approach 2:
The autofocus and optical image stabilization mechanisms are merged into a single integrated system. The voice coil motor and permanent magnets provide a unified actuation system that can produce forces in multiple directions, eliminating the need for separate mechanical assemblies and reducing overall device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively minimizes parasitic motion, enhancing image quality by accurately controlling the lens assembly's movement along the optical axis and in orthogonal directions, thereby improving autofocus and optical image stabilization performance.
Implementation Method 1
the permanent magnets each generate a magnetic field of a respective permanent magnet field strength
Implementation Method 2
a plurality of permanent magnets mounted to the actuator base through a magnet holder assembly... allowing for precise movement of the lens assembly
Data Source
AI summary
In some embodiments, a camera includes a lens assembly in a lens carrier, an image sensor for capturing a digital representation of light transiting the lens, and a voice coil motor. In some embodiments, the voice coil motor includes a spring suspension assembly for moveably mounting the lens carrier to an actuator base, a plurality of permanent magnets mounted to the actuator base through a magnet holder assembly and a focusing coil fixedly mounted to the lens carrier and mounted to the actuator base through the suspension assembly. In some embodiments, the permanent magnets each generate a magnetic field of a respective permanent magnet field strength, and the magnet holder assembly generates a holder magnetic field of a holder magnetic field strength.